Metallic structure and photodetector

Abstract

In a metallic structure including a metallic nano-chain with plasmon resonance absorption, a metallic nanoparticle forming the metallic nano-chain is formed in a circular, triangle, or rhomboid shape. The wavelength selectivity can be increased also by forming a closed region by mutually linking all of metallic nanoparticles that are mutually linked with bottlenecks. In a photodetector, a photodetection unit including a current detection probe, a nano-chain unit, and a current detection probe is arranged on a substrate. The nano-chain unit is a metallic structure with plasmon resonance absorption, where metallic nanoparticles are mutually linked with bottlenecks. Each current detection probe has a corner whose tip is formed with a predetermined angle, and this corner is arranged to face the tip of the nano-chain unit, i.e., a corner of the metallic nanoparticle. Photodetection with high wavelength selectivity is performed based on a change in the initial voltage of the current-voltage characteristic.

1. A photodetector comprising:
 a plurality of metallic nanoparticles formed in any one of a circular shape, a triangle shape and a rhomboid shape; 
 a nano-chain unit having the plurality of metallic nanoparticles mutually linked with a plurality of bottlenecks; and 
 a photodetection unit having a positive and a negative current detection probes arranged on a substrate, wherein 
 the nano-chain unit with plasmon resonance absorption is sandwiched between the positive and the negative current detection probes. 
 
     
     
       2. The photodetector according to  claim 1 , wherein
 both ends in a length direction of the nano-chain unit are sandwiched between the positive and the negative current detection probes, and 
 a metallic nanoparticle at one end of the nano-chain unit and a tip of at least one of the current detection probes are arranged with a predetermined, gap therebetween. 
 
     
     
       3. The photodetector according to  claim 1 , wherein a tip of a metallic nanoparticle at one end of the nano-chain unit is arranged so as to be sandwiched between the positive and the negative current detection probes with a predetermined gap therebetween. 
     
     
       4. The photodetector according to  claim 1 , wherein
 both sides of either one of the metallic nanoparticles of the nano-chain unit are sandwiched between the positive and the negative current detection probes, and 
 at least one of the current detection probes and one side surface of the metallic nanoparticle are arranged with a predetermined gap therebetween. 
 
     
     
       5. The photodetector according to  claim 1 , wherein a predetermined voltage is applied between the positive and the negative current detection probes. 
     
     
       6. The photodetector according to  claim 1 , further comprising a plurality of photodetection units formed to have different absorption wavelengths of plasma resonance absorption caused by their respective nano-chain units.